Last Updated on 2020-11-08 by aeno
When you’re running Magento 2 inside a Docker container (for example for local development) and you’re using a non-standard TLS port (or SSL port) like 44333, then your back-end adminhtml route will trigger a 404 error.

The Solution: Even if it seems to be redundant, set a custom admin URL.
Set admin/url/use_custom
to 1
and admin/url/custom
to your back-end’s full URL including non-standard port: https://my.site:44333/admin
.